Holding devices of this type are frequently required in performing surgical interventions in order to hold medical instruments of various types, such as retractors, video cameras, or endoscopes, in a particular position for an extended period. Owing to the jointed design of the holding devices, it is possible for the surgeon to position with exactitude the medical instrument that is held in the instrument intake and, by blocking the joint or joints, to fix the position of the holding device that has been selected.
A generic holding device is known for instance from U.S. Pat. No. 6,587,750 B2. This known device is a remote-controlled surgical robotic device the handle of which can be actuated by a touch sensor. The disadvantage of this known construction is that positioning errors in the area of the medical instrument can occur, especially with long and multi-partite carrier arms, if mere touching of the handle immediately converts the holding device into a movable position.
An additional holding device is known, for instance, from DE 195 26 915 B4. With this known holding device, the joint parts are blocked with respect to one another by friction locking owing to the spring force of at least one spring element. Releasing the blocking occurs pneumatically by means of blades positioned in the joint, which when impacted for instance by compressed air can ensure separation of the friction lock. Although holding devices of this type have proven themselves in the art, it is precisely the contact surfaces that are to be held together by the friction lock which constitute problems in cleaning because, with the high contact forces that are required to produce a reliable friction lock, scratches can be caused in the contact surface which in turn can form germ cells for impurities.